ONUCA was established by
Security Council resolution
644 (1989) of 7 November 1989. The Group's mandate was to conduct
on-site verification of compliance by the Governments of Costa Rica, El
Salvador, Guatemala, Honduras and Nicaragua with their security undertakings
contained in the Esquipulas II Agreement, namely (a) the cessation of
aid to irregular forces and insurrectionist movements, and (b) the non-use
of the territory of one State for attacks on other States. The latter
undertaking was to include preventing the establishment or use of facilities
for radio or television transmissions for the specific purpose of directing
or assisting the military operations of irregular forces or insurrectionist
movements in any of the five countries.

On 27 March 1990, the Council,
by its resolution
650 (1990), authorized, on a contingency basis, an enlargement of
the mandate of ONUCA and the addition of armed personnel to its strength
in order to enable it to play a part in the voluntary demobilization of
the Nicaraguan Resistance.

On 20 April 1990, following
the signing by the Nicaraguan parties of a complex of agreements relating
to the voluntary demobilization of the members of the Nicaraguan Resistance
in Nicaragua, the Security Council, by its resolution
653 (1990), decided to expand ONUCA’s mandate to include additional
tasks of monitoring the ceasefire and separation of forces, and the demobilization
process.

After the completion of the
demobilization process in June/July 1990, ONUCA continued to implement
its original tasks and contribute to the peace efforts in the region.
The mandate of the Mission was terminated in January 1992.